We have been studying the relationship between pregnancy and vitamin B-6 nutriture in mice, and this proposal extends our ongoing studies. We will concentrate on assessment of vitamin B-6 nutritional status in pregnancy, although the methods we propose are applicable to infants and children. From studies in mice we will determine the relationship between dietary intake of vitamin B-6 and several predictor indices of vitamin B-6 nutritional status. We plan to measure the concentrations of the six forms of vitamin B-6 in plasma, erythrocytes, liver and brain; and erythrocyte alanine and aspartate aminotransferase activities in erythrocytes separated according to age in pregnant mice and non-pregnant controls. Mice will be fed one of five dietary levels of vitamin B-6 (pyridoxine-Hcl) to determine the effect of dietary intake on these nutritional status indices. A parallel analysis of these predictor indices will be performed on blood samples obtained from pregnant white, black and Hispanic women. The goal of these studies is to determine from experiments in animals which predictor indices best reflect vitamin B-6 nutritional status, and to verify these results with human patients. During pregnancy most women have some degree of deficiency of vitamin B-6 compared to age-matched non-pregnant women. The cause of this deficiency is not known. Shunting of the vitamin from the mother to the fetus is involved, but since it does not respond well to dietary supplementation, reduced synthesis or enhanced metabolism may contribute to the pregnancy-associated vitamin B-6 deficiency. The lowered vitamin B-6 status may simply represent normal, relatively benign, physiological changes in pregnancy. However, the deficiency is greater in toxemia of pregnancy, indicating a potential role for vitamin B-6 in the mediation of this condition. Currently, there are no generally acceptable tests of vitamin B-6 nutritional status in pregnancy, and the goal of this application is to assess the utility of several potential status indicators.